Project suggestion: set utils

[Paweł Lampe]

From time to time everybody uses shell commands to work with data 
stored in files.

cat, grep, cut, tr, comm etc. helps to deal with that.

Last month I was crawling lots of data across the web. Later on I had to 
split data by some delimiter and make some set-like operations: UNION, 
INTERSECTION etc. Obviously I did. But it hurt a bit. There is still no 
tool to treat files like sets. Ofcourse I may use sort of utils and 
combine them, but in more complex cases I would like to use something 
dedicated. For example look at this: 
http://unix.stackexchange.com/questions/11343/linux-tools-to-treat-files-as-sets-and-perform-set-operations-on-them 
- few simple operations and there are lots of ideas. But what if I would 
like to (X+Y)*Z and not to create temporary files ?

My Idea is about set utils; a set of utilities to deal with sets or 
maybe one utility to 'rule them all'.

How about it ?